Key issues in substrate and liquid phase epitaxy of Hg1-xCdxTe from Hg-rich and Te-rich solutions

In this paper we review the key issues in CdTe substrate which influence the duality of mercury cadmium telluride epilayer grown by liquid phase epitaxy. The issues are crystallinity, defects such as tellurium precipitates and impurities. We discuss the conditions to grow good duality epilayers of Hg1-xCdxTe (x = 0.23) from Hg-rich and Te-rich solutions at 470 degrees C. The physical parameters such as surface morphology, composition, thickness, X-ray full width at half maximum and broadening parameter from electrolyte electroreflectance obtained in two cases are compared. It is shown that epilayers grown from Hg-rich solution have, better surface morphology, lower growth rate and crystallinity and broadening parameter similar to layers grown from Te-rich solution. Compositionally epilayers grown from Te-rich solution are more uniform. The quality of an epilayer grown from Te-rich solution deteriorates faster than grown from Hg-rich solution when the cooling rate is increased in excess of 2 degrees C/h.